Many grinding machines in use today, especially those used to effect the so-called "creep feed" method of grinding, employ a grinding wheel mounted for rotation on a generally horizontally disposed spindle. During the grinding process, the grinding wheel diameter decreases. When these machines are operated to grind workpieces at high stock removal rates and/or with continuous dressing of the grinding wheel, the use of larger diameter grinding wheels and larger motors is usually desired. As the wheel diameter decreases, the entire grinding wheel spindle must be moved vertically downwardly toward the workpiece to continue grinding.
Maintaining tolerances with the larger grinding wheel and drive motor becomes difficult because the machine must accommodate movement of the larger and heavier grinding wheel, spindle, and motor toward and away from the workpiece during the grinding operations.
Such conventional grinding machines also are not particularly suitable for permitting rapid and/or fully automatic replacement of machine components as necessary to accommodate different workpieces.
Also, with most conventional grinding machines having a horizontally disposed grinding spindle, a workpiece is typically ground on a table at a location on the lowest point of the grinding wheel. Typically, it is not feasible or convenient to grind another workpiece until the first workpiece is completely removed and replaced by the new workpiece. Accordingly, the actual grinding of a workpiece does not occur during those periods of time when one workpiece is being removed from the machine and another workpiece is being mounted in the machine. This results in a degree of production inefficiency.
It would be desirable to provide an improved method and apparatus for grinding a plurality of workpieces at high production rates. It would be advantageous if such an improved method and apparatus could efficiently grind a plurality of workpieces while at the same time keeping to a minimum the power required for operating the grinding machine. However, to the extent that it would be desirable to provide a relatively large grinding wheel for effecting higher stock removal rates with or without continuous dressing of the wheel, it would be beneficial if such an improved method and apparatus could accommodate operation within desired machining tolerances and yet permit rapid and/or fully automatic replacement of machine components.
It would also be advantageous to provide an improved grinding method and apparatus which would permit relatively uniform transfer of heat and accommodate thermal expansion with a minimum of deleterious effects. Further, it would be beneficial if such an improved method and apparatus could provide for substantially automated machining, loading, and unloading of workpieces, as well as changing of the grinding wheel.